Common Channel Signaling System No. 7 (or SS7) is a global standard for telecommunications defined by the International Telecommunication Union Telecommunication Standardization Sector (or ITU-T). The standard defines the procedures and protocol by which network elements in the public switched telephone network (PSTN) exchange information over a digital signaling network to effect wireless (cellular) and wireline call setup, routing and control. The ITU definition of SS7 allows for national variants such as the American National Standards Institute (ANSI) and Bell Communications Research (Telcordia Technologies) standards used in North America, the European Telecommunication Standards Institute (ETSI) standard used in Europe, and the Telecommunication Technology Committee (TTC) standard used in Japan. SS7 messages are traditionally exchanged between network elements over 56 or 64 kilobit per second (kbps) bi-directional channels called signaling links, or can be exchanged over the Internet Protocol or over ATM in a point-to-point or networking fashion using adaptation layers. As SS7 network evolves, more transport methods and protocols can be defined.
Each signaling point in the SS7 network is uniquely identified by a numeric point code. Point codes are carried in signaling messages exchanged between signaling points to identify the source and destination of each message. However, as the network grows its size and complexity, new point codes would eventually become scarce and, thus creating such new point codes would be very expensive. Re-architecturing a signaling network, i.e. adding a new network (or network elements) or deleting a part of the network could also be time consuming and often requires reprogramming the switches according to the new network architecture, thus it is desirable to have a method and apparatus for expanding the network without going through such network rearchitecturing.
There are a couple of prior art systems attempted to solve such issues. For example, U.S. Pat. No. 6,987,781, entitled “Methods and Systems for Routing signaling Messages in a Communication Network Using Circuit Identification Code (CIC) Information”, issued to Miller et al on Jun. 17, 2006 relates to a routing node for receiving, processing and subsequently transmitting SS7 signaling messages destined for a Media Gateway Controller type network element, where the network element is a CIC routing node adapted to receive ISUP messages from an associated SS7 network and determine the routing destination of the messages based on originating point code (or OPC), destination point code (or DPC) and circuit identification code (or CIC). However, in this prior system, such conversion is limited to ISUP messages, thus it would not be able to extend the services using other message types, such as SCCP or TCAP messages, thus this is a limitation of this solution.